W
EIGHTING
F
ACTORS FOR THE
C
RITERIA OF A
B
UILDING
S
USTAINABILITY
A
SSESSMENT
T
OOL
(DGNB)
J
OSÉA
NTÓNIOP
OMBINHOM
IRANDADissertação submetida para satisfação parcial dos requisitos do grau de MESTRE EM ENGENHARIA CIVIL —ESPECIALIZAÇÃO EM CONSTRUÇÕES
Orientador: Professora Eva Sofia Botelho Machado Barreira
Coorientador: Professor Conrad Voelker
2
MESTRADO INTEGRADO EM ENGENHARIA CIVIL 2012/2013
DEPARTAMENTO DE ENGENHARIA CIVILTel. +351-22-508 1901 Fax +351-22-508 1446
miec@fe.up.pt
Editado por
FACULDADE DE ENGENHARIA DA UNIVERSIDADE DO PORTO
Rua Dr. Roberto Frias 4200-465 PORTO Portugal Tel. +351-22-508 1400 Fax +351-22-508 1440 feup@fe.up.pt http://www.fe.up.pt
Reproduções parciais deste documento serão autorizadas na condição que seja mencionado o Autor e feita referência a Mestrado Integrado em Engenharia Civil -
2012/2013 - Departamento de Engenharia Civil, Faculdade de Engenharia da Universidade do Porto, Porto, Portugal, 2013.
As opiniões e informações incluídas neste documento representam unicamente o ponto de vista do respetivo Autor, não podendo o Editor aceitar qualquer responsabilidade legal ou outra em relação a erros ou omissões que possam existir.
Este documento foi produzido a partir de versão eletrónica fornecida pelo respetivo Autor.
i ACKNOWLEDGMENTS
This research project would not have been possible without the support of many people. I would like to express my gratitude, in particular to:
My supervisor, Prof.Eva Barreira for the time, continuous support, motivation and suggestions. My co-supervisor Prof. Conrad Voelker for the support, enthusiasm, guidance and without whose knowledge and assistance this work would not have been possible.
Finally, to my family, especially my parents and brothers for their understanding and support through the duration of my studies.
iii ABSTRACT
This work relates to the Building Sustainability Assessment tools in particular to the weighting factors of criteria used on those tools.
The aim of this dissertation is to develop new weighting factors for the criteria considered in the assessment of new office and administrative buildings. For that purpose, ten different criteria were chosen, related to building physics, in which the study has focused.
With this objective, this work comprises of two main stages: (1) study of the criteria and definitions of the weighting factors for criteria and (2) implementation of the weighting factors for criteria on the DGNB system and analysis of the results with the new weighting factors. Therefore, at the first stage a study was made of the different existing Building Sustainability Assessment tools and of the criteria considered through a realization of a questionnaire addressed at experts in different fields of building constructions, which made it possible to define the new weighting factors for the criteria. At the second stage, the implementation of the new weighting factors of criteria on the DGNB system was made, applying it to a specific case and then a comparison between it and the original results was made.
v RESUMO
Este trabalho está relacionado com as ferramentas de avaliação de sustentabilidade de edifícios e particularmente com os fatores de ponderação de critérios utilizados nestas ferramentas. O objetivo desta dissertação é o desenvolvimento de novos fatores de ponderação para os critérios utilizados na avaliação de novos edifícios administrativos e de escritório. Nesse sentido, foram escolhidos dez diferentes critérios, relacionados com a física das construções, nos quais este trabalho se foca.
Este trabalho compreende duas fases principais: (1) estudo dos critérios e definição dos fatores de ponderação para os critérios e (2) implementação dos novos fatores de ponderação dos critérios no sistema de certificação DGNB e análise dos resultados com estes novos fatores. Portanto, na primeira fase foi feito um estudo das diferentes ferramentas de avaliação de sustentabilidade em edifícios existentes e dos critérios que estas consideram e através de um inquérito destinado a especialistas de diferentes campos da física das construções foi possível definir os novos fatores de ponderação.
Na segunda fase foi feita a implementação destes novos fatores de ponderação no sistema de certificação alemão DGNB, e a aplicação deste sistema a um caso específico bem como uma posterior análise comparativa entre os novos resultados e os originais.
vii TABLE OF CONTENTS ACKNOWLEDGMENTS ... i ABSTRACT ... iii RESUMO ... v
1. INTRODUCTION ... 1
1.1. General considerations ... 11.2. Motivation and objective ... 2
1.3. Structure ... 2
2. L
ITERATURE
R
EVIEW
... 3
2.1. Sustainable Construction ... 3
2.1.1. Evolution of the Concept ... 3
2.1.2. Principles and Definitions ... 4
2.1.3. Application Stages ... 5
2.1.4. Advantages and Disadvantages ... 7
2.2. Sustainable Construction Assessment ... 8
2.3. Existing Building Sustainability Assessment Tools ... 9
2.3.2. DGNB Certification System ... 9
2.3.3. Other Existing Building Sustainability Assessment Tools ... 13
3. M
ETHODOLOGY
... 19
3.1. Introduction ... 19
3.2. Criteria... 19
3.2.1. Energy Demand ... 20
viii
3.2.3. Indoor Air Quality ... 21
3.2.4. Acoustic Comfort ... 21
3.2.5. Visual Comfort ... 21
3.2.6. User Influence on Building Operation ... 22
3.2.7. Sound Insulation ... 22
3.2.8. Building Envelope Quality ... 23
3.2.9. Fire Protection ... 23
3.3. Questionnaire ... 24
4. N
EW
W
EIGHTING
F
ACTORS
... 29
4.1. Analysis of the Results ... 29
4.1.1. Data Collection and Simple Analysis ... 29
4.1.2. Criteria Analysis ... 33
4.1.3. Overall View of the Results ... 46
4.2. Proposal for the New Weighting Factors ... 48
4.3. Implementation of the New Weighting Factors on the DGNB Certification System ... 51
5. C
ONCLUSIONS
... 57
ix LIST OF FIGURES
Figure 1- Sustainability Objectives ... 4
Figure 2 - Degree of compliance ... 11
Figure 3- Global Performance Degrees of the LIDERA Certification System ... 17
Figure 4 - Homepage of the questionnaire ... 24
Figure 5 - First question of the questionnaire about the importance of the criteria ... 25
Figure 6- Extract of the questionnaire - Question about the frequency of occurrence of deficiencies on buildings ... 26
Figure 7- Extract from the questionnaire- Extent of the deficiencies ... 27
Figure 8- Gender distribution of the people surveyed ... 29
Figure 9- Age distribution of the people surveyed ... 29
Figure 10- Nationalities of the people inquired ... 30
Figure 11- Fields of specialization of the people surveyed ... 31
Figure 13- BSA tools experienced ... 31
Figure 12- Experience with the BSA tools ... 31
Figure 14- Type of experience with the BSA tools ... 32
Figure 15- Failures of the BSA tools ... 33
Figure 16- Importance of the Criteria – Overall ... 34
Figure 17- Frequency of deficiencies - Overall ... 35
Figure 18- Extent of personal suffering with the deficiencies – Overall ... 35
Figure 19- Importance of the Criteria - People with experience with the BSA tools... 37
x
Figure 21- Extent of personal suffering with the deficiencies - People with experience with the
BSA tools ... 39
Figure 22- Importance of the Criteria - People with experience with the DGNB system ... 41
Figure 23- Frequency of the deficiency – People with experience with DGNB ... 42
Figure 24- Extent of personal suffering with the deficiencies - People with experience with the DGNB system ... 42
Figure 25- Importance of the criteria - Germany ... 44
Figure 26- Importance of the Criteria - North Europe Countries ... 45
Figure 27- Importance of the Criteria- South Europe Countries ... 46
Figure 28- Average importance of the 10 criteria ... 47
Figure 29- Evaluation Matrix of the DGNB system for New Office and Administrative Buildings, version 2009 ... 52
xi LIST OF TABLES
Table 1 - Overview of all schemes ... 10
Table 2- DGNB Certification System Criteria ... 12
Table 3- List of the 10 Criteria on study and respective deficiencies associated ... 26
Table 4- Correlations between variables – Overall analysis ... 36
Table 5- Correlations between variables – People with experience with the BSA tools ... 40
Table 6- Correlations between variables – People with experience with the DGNB system ... 43
Table 7- Importance of the Criteria - Overall Analysis ... 48
Table 8- New weighting factors of the 10 criteria ... 49
Table 9- Comparison between the new weighting factors and the ones present on the DGNB Certification System ... 50
Table 10- Real case assessment - Original results Vs. Results with the new weighting factors . 53 Table 11- Hypothetical case 1 - Original results Vs. Results with the new weighting factors – Results with the maximum scores achieved (10) by the 11 criteria studied ... 54
Table 12- Hypothetical case 2 - Original results Vs. Results with the new weighting factors – Results with the minimum scores achieved (0) by the 11 criteria studied ... 55
xiii LIST OF ACRONYMS
BMVBS - Federal Ministry of Transport, Building and Urban Affairs BRE - Building Research Establishment
BREEAM – Building Research Establishment Environmental Assessment Method BSA – Building Sustainability Assessment
CASBEE – Comprehensive Assessment System for Built Environment Efficiency DGNB – German Sustainable Building Council
HQE – High Quality Environment standard
LEED – Leadership in Energy & Environmental Design LIDERA – Lead for the Environment
SBTool – Sustainable Building Tool
1
1
INTRODUCTION
1.1. GENERAL CONSIDERATIONS
The development of society, at the level of population and quality of life, provided the uncontrolled rising consumption of resources and materials available in nature.
With the oil crisis in the 1970s, there began to be a rise in awareness about the environment and on saving energy. Thus, with awareness of the environment, the future of the planet and its resources, humanity began to take a greater role in our society.
The construction sector is one of the most responsible for the negative environmental impact that is felt on the planet, due to the large consumption of energy and materials, as well as pollutant emissions of building, throughout the life cycle of a building.
These concerns have warned for the need to introduce the concepts of sustainability and sustainable development in all sectors, particularly in the construction sector.
Thus arises, in this context, the concept of sustainable construction. Sustainable construction is a concept that relies on the need to find a balance between environment, economic and social aspects throughout a building’s life-cycle. Thus, sustainable construction aims to reduce the environmental impact of a building from design, construction, operation, maintenance, renovation and deconstruction, optimizing the economic aspects and the building comfort. To respond to the need to put into practice this concept, several systems have been developed and applied to evaluate the building’s performance in respect to its sustainability, the building sustainability assessment (BSA) tools.
This work focuses on the study of the weighting factors of criteria used on the BSA tools, in which an approach to different BSA tools will be made as well as a study of some of the criteria present in those tools.
2
1.2.MOTIVATION AND OBJECTIVE
The aim of this work is the study of the existing building sustainability assessment tools and the criteria considered as well as a proposal for new weighting factors for the criteria of office buildings. Thus, this study will be focused on ten criteria related to building physics.
The study is also aimed at the implementation of new weighting factors, for the criteria, on the German BSA tool, DGNB, for a comparison between the original results and the results with the new weighting factors.
This study arises because the weighting factors of the criteria considered by the German certification system was decided by a restricted group of people and these weighting factors might not be the most appropriate, resulting in some distrust in them.
With this work, it is expected that the new weighting factors may be more reasonable and may more accurately transmit the weight of each criterion and thus the overall score of the office building will be closer to the reality.
1.3.STRUCTURE
In Chapter 1, an introduction and a first approach are made on the theme of this work. It describes the objectives and the proposed targets of achievement as well as the structure of this thesis.
In Chapter 2, concepts and principles of sustainable buildings are present, as well as the advantages and the importance of the assessment tools for sustainable buildings. Furthermore, a description of the most important existing building sustainability assessment tools are also made.
In Chapter 3 contains the development part of the thesis, with a description of each one of the ten criteria chosen to be studied and the methodology used. In this chapter, the questionnaire developed on this study and all the questions presented on the questionnaire are described. In Chapter 4 the obtained results as well as the discussion on them are presented. Present in this chapter is also the proposal for the new weighting factors for the ten criteria studied as well as their implementation on a DGNB certification system's specific case and two hypothetical cases with a comparison between the new results and the original ones.
In Chapter 5 the conclusions of this research are presented. There are also some recommendations for further work and possible criticism of this project.
3
2
L
ITERATURE
R
EVIEW
2.1.SUSTAINABLE CONSTRUCTION 2.1.1.EVOLUTION OF THE CONCEPT
With the environmental degradation and the concerns about the natural resources becoming increasingly important, international conferences on the environment started to be realized. In 1972 the first conference with good results took place. It was the United Nations Conference on the Human Environment – the Stockholm Conference.
In 1987 the Brundtland Report arises [1], “Our common future: The world commission on environment and development”. This report seeks to recapture the spirit of the Stockholm Conference in which the definition of sustainable development arose:
“Development that meets the needs of the present without compromising the ability of future generations to meet their own needs”.
In this document measures to promote the sustainable development were defined, focusing mainly on energy and consumption of non-renewable resources [1].
Another conference that changed the perception about sustainable development was the Rio de Janeiro Conference, in 1992. At this conference, environmental degradation and the solutions for a sustainable development were discussed. It was at this conference that the “Agenda 21” arose, which was a plan to be applied at global, national and local level [2]. This document was intended to be a global action plan for sustainable development, containing recommendations and specific references with the objective of promoting the environmental regeneration and social development [3].
In 1996, the “Habitat Agenda II” arose, in the Istanbul conference. This document shows the concerns about the sustainability of population clusters and contains several sections devoted to the construction industry and how national governments should encourage industry towards sustainability [3] [4].
The sustainable development is a concept that is based on three main dimensions: economic, social and environmental (Figure 1). On the environmental dimension, the intent is to reduce the
4
consumption of resources, the production of waste and to preserve the biodiversity. The social domain is about the understanding of social institutions and their role in development, as well as well-being, health and education. The economic dimension is about the impact that the economic growth has on society and the environment [3].
Figure 1- Sustainability Objectives
Nowadays, our planet faces an environmental challenge whose lack of resolution could result in the end of human civilization, as we know it.
The world population has been experiencing a strong growth since 1950. In 1950 the world population was 2.500 billion people, currently it is at over 7.000 billion people and it is expected that this number will rise to over 9.000 billion people by 2050.
This population growth, together with the satisfaction patterns of people ever higher, has led to an excessive consumption of the natural resources of our planet. These facts will cause serious consequences on the environment and also the development process of societies that aims to be sustainable.
The construction sector is one of the most responsible for the consumption of natural resources (water, energy, materials, etc.) and it is also a major producer of waste and pollutant emissions for the environment. Thus, it is of great importance to intervene in this sector.
2.1.2.PRINCIPLES AND DEFINITIONS
The term “sustainable construction” was defined for the first time in 1994, by Professor Charles Kibert to describe the responsibilities of the construction industry in the concept and objectives of sustainability [5]:
“Sustainable construction is the responsible development and management of a healthy built environment, based on the efficient use of the resources and on the ecological principles” The sustainable construction concept is based on the development of economically viable models that enable the construction sector to propose solutions for the environmental problems
5 of our time, without having to give up modern technologies and of the creation of buildings that respond to the needs of its users. In other words, sustainable construction aims to reduce the environmental impact of buildings over its lifetime, while optimizing the costs and the comfort of the users.
While the standard building practices are guided by concerns related to the short term economic aspects, in order to achieve maximum profit, the sustainable construction is based on practices that have as major importance long term aspects as the economic and environmental aspects as well as the user’s comfort, the quality and efficiency of the building. Thus, the sustainable construction seeks to match the reduction of consumption of energy, water and the production of waste, with the user’s comfort and needs and the life-cycle costs of the building.
Sustainable construction is based on a set of fundamental principles such as [6]:
Energy and water efficiency – minimize the use of energy, use renewable energies like solar, biomass and wind energy and increase the energetic efficiency of the building. Minimize the use of water and reuse and recycle used water;
Waste management – minimize the generation of waste and efficient management of the waste produced;
Indoor Comfort –the site and shape of the building are very important to benefit from favorable solar orientation, wind exposure and natural illumination and ventilation. It is also important to provide health and well-being indoor conditions to its occupants, as well as provide excellent thermo-acoustic conditions in order to improve life quality and comfort for the user;
Use of environmentally friendly materials - use eco-friendly and recyclable materials and non-toxic materials that support the protection and cooperation with natural systems.
Durability of buildings – use durable and flexible materials to allow the adjustment to different uses. Plan conservation and maintenance interventions on the building.
Costs – Reduce the costs for sustainable solutions otherwise the solution will not be competitive with the traditional buildings. Increase productivity and decrease the length of construction with simple constructive solutions.
By fulfilling all of these fundamental principles it is possible to achieve a sustainable construction [7].
Thus, the key elements of sustainable construction are: the reduction of energy and natural resources consumption, the conservation of the environment and biodiversity, the maintenance of the quality of the built environment and health management of the indoor environment.
2.1.3.APPLICATION STAGES
2.1.3.1 Introductory note
To be considered a sustainable construction, the building has to be thought out to minimize the environmental impacts and its natural resources and to improve the building comfort, necessarily in all the phases of a building’s life-cycle [4].
Thus, the fundamental principles of a sustainable construction must be present in the project, construction, operation, maintenance, renovation and deconstruction phases through the
6
application of rigorous methods and constructive processes, the use of renewable materials and an efficient monitoring and evaluation [4] [5].
The sustainable building process requires a correct and constant monitoring of all stages of the building life-cycle in order for it to be possible to assess the efficiency of the choices made in the process, from the project to demolition and if necessary to correct the eventual deviations from the desired result levels [8].
The impacts generated by a construction occur from the construction phase, through to the use, maintenance and renovation phases to the demolition phase. All these stages, with different intensities, have environmental impacts and most of these impacts are determined at the project stage [9].
2.1.3.2. Project
On the project stage it is very important at first, to be aware of the characteristics of the location, as well as the sun and wind exposure, rainfall, climate, and surrounding noise in order for the best constructive solutions to be met in order to optimize the benefits of the natural conditions of the place [10].
After knowing the characteristics and conditions of the place, the constructive solutions to be adopted are defined, focusing on solutions with less impact on the environment [10].
Thus, the main activities on this stage are: location, solar and wind orientation, choice of eco-friendly materials, determination of the level of thermal efficiency of the building, natural ventilation; rainwater harvesting and reuse of water systems [9].
2.1.3.3. Construction
At this stage the strategies defined on the previous phase are implemented.
This process must be very controlled since it is a stage where there are many participants and higher probability of occurring errors. Some errors may compromise the efficiency of the building or some of its functionalities, so it is important to minimize them [10].
At this stage, a strong monitoring of the work process is important so that it is carried out as defined in the project in order to achieve the expected results.
The main measures to be taken at this stage are: strict control of the implementation and planning of the work; strict control of the technological process of construction; use of materials and equipment that reduce the production of waste and pollution [9].
2.1.3.4. Operation/Use
As this phase is the longest, its impacts also have greater durability in the consumption of resources, pollutant emissions and the accumulation of material level.
The strategies defined in the previous phases are now put into practice, like the efficient use of water, for example.
7 The elaboration of a manual of use for the adjustment of the protective solar systems, temperature regulation, etc., is a good measure to take [10].
2.1.3.5. Maintenance and Renovation
This is the stage that focuses on the procedures to be adopted in order to increase the durability and the efficiency level of the building and therefore its life-cycle.
It is at this stage that the maintenance manual is applied and defined in the project. Where the action, maintenance work and renewal is defined to be performed, as well as its periodicity [10].
2.1.3.6. Demolition
This is the last stage of the building life-cycle at which point the resulting materials should be ensured and waste is sent for recycling, in order to minimize their impact on the environment. Again, this process should be defined at the design stage.
2.1.4.ADVANTAGES AND DISADVANTAGES
The benefits of sustainable construction may be grouped in three different fronts: environmental, economic and social [11].
Environmental benefits:
Pollutant emissions reduction; Water conservation and management; Waste reduction;
Natural resources preservation. Economic advantages:
Energy and water savings; Increased property values;
Increased employee productivity and satisfaction;
Optimize the economic performance of the building life-cycle. Social advantages:
Improved air quality, thermal and acoustic comfort of the building; Improved comfort and health of the user;
Healthier Lifestyles and Recreation.
The disadvantages of sustainable construction are mainly related with the initial costs of the construction. The lack of offer of eco-friendly materials makes them more expensive, which can cause the prices to be much higher than standard building materials [12].
Apart from the initial costs of the construction, finding a lender who offers loans for this kind of building may be difficult [12].
8
The availability of materials in more distant areas of production centers is directly associated with the high cost of products. The greater the distance, the higher the transportation cost of materials [12].
Time may also be a disadvantage, since eco-friendly materials may take extra-time to be found and the builder and/ or homeowner might have a deadline.
2.2.SUSTAINABLE CONSTRUCTION ASSESSMENT
Even countries that are believed to have the full domain about the sustainable construction had no means to check "how green" their buildings were. This was the first sign of the need to assess the environmental impact of a building [3].
Buildings projected to be sustainable buildings had most of the times higher energy consumption than standard buildings, as was proven years later.
The creation of sustainable construction assessment tools started with the agreement between governments and researchers about the performance classification combined with the certification systems [3].
This step on the environmental assessment development was instrumental in the formulation of guidelines and methods for sustainable construction, their quality criteria and methods for assessment and verification of those, leading to the creation of several models and systems for the assessment of sustainable construction [3].
Until 1990, little attempt had been made to simultaneously assess a broad range of environmental considerations, based on explicit criteria, and make an overall performance summary.
The sustainable construction field has experienced a remarkably quick growth since the introduction of the United Kingdom system - BREEAM – and in the past twenty years have witnessed a large increase in the number of assessment tools.
The use and development of building environmental assessment methods now represent a central focus for the building environmental design and performance debate [13].
The aim of sustainable construction assessment is the recognition and certification of buildings that adopt sustainable practices, i.e., buildings that take into account the economic, environmental and social aspects.
The assessment is made through the application of assessment systems that aim to guarantee the sustainability during the whole building's life-cycle.
These systems have contributed enormously to furthering the promotion of higher environmental expectations, given focus to green building practices and have directly and indirectly influenced the performance of buildings.
These systems play a valuable role by providing a clear declaration of the key environmental considerations and their relative priority, assisting in the design process, as well as enabling the building performance to be described comprehensively [13].
9 2.3.EXISTING BUILDING SUSTAINABILITY ASSESSMENT TOOLS
2.3.1INTRODUCTORY NOTE
In the last years, sustainable construction is assuming great importance and therefore the assessment tools have known a great development and are an important challenge for the market. These tools, in addition to the assessment, also allow the certification of buildings, in regards to sustainability.
The building sustainability assessment tools have emerged in Europe and quickly spread through other countries, mainly Canada and the USA, and also in countries like Japan, Australia, among others, which also already have their own certification systems [14].
Among the main systems, the following stand out:
DGNB Certification System (DGNB - German Sustainable Building Council) – Certification system developed in Germany;
BREEAM (Building Research Establishment Environmental Assessment Method)- Certification system developed in the United Kingdom;
LEED (Leadership in Energy & Environmental Design) – Certification system developed in the USA;
CASBEE (Comprehensive Assessment System for Built Environment Efficiency) – Certification system developed in Japan;
HQE (High Quality Environment standard) – Certification system developed in France; LIDERA (Lead for the Environment) – Certification system developed in Portugal; SBToolPT (Sustainable Building Tool, Portugal) – Portuguese adaptation of the
international system SBT (Sustainable Building Tool).
These systems work through the definition of a set of performance criteria of the building, grouped into different sets of criteria forming a logical structure, which allow a partial and global final evaluation of the building. Each one of these criteria has associated a weighting factor, according to their importance in terms of sustainability. The more important the criterion the greater will be its weighting factor [6].
The assessment is made through the attribution of a number of points to each criterion within a defined range, depending on the performance of the building. The overall score of the building is obtained through these points or scores of each of the criteria [6].
2.3.2.DGNBCERTIFICATION SYSTEM
2.3.2.1. Introduction
This system was developed by the German Sustainable Building Council (DGNB) together with the Federal Ministry of Transport, Building and Urban Affairs (BMVBS) to be used as a tool for the planning and evaluation of buildings with a comprehensive perspective on quality [15]. The purpose of the DGNB was to create a second generation certification system, which emphasizes on an integrated view over the whole life-cycle of the building and with focus on
10
the following main groups of criteria that affect the evaluation: ecology, economy, socio-cultural and functional topics, techniques, processes and location [7] [8].
The DGNB is a clearly arranged and easy to understand rating system, covering all the relevant topics of sustainable construction, and awards outstanding buildings in the categories with bronze, silver and gold [16].
This certification system was initially developed for new office and administration buildings, in 2008. This version emerged from the pilot phase of the system and the sustainability of office and administration buildings were evaluated based on 49 criteria [8]. The current version considers a total of 63 criteria but only uses 48, because the scientific principles for 15 criteria are currently being developed.
But the DGNB system is very flexible. Different buildings have different characteristics and requirements that need to be taken into account. It is for this reason that DGNB Certification System has developed several “schemes” depending on the type of building (Table 1) [17].
Table 1 - Overview of all schemes
Existing Buildings New Buildings New Districts Office and administrative
buildings, Retail Buildings, Industrial Buildings and
Residential Buildings.
Educational facilities, Office and administrative buildings,
Office and administrative buildings (with modernization
measures), Retail Buildings, Hotels, Industrial buildings,
Hospitals, Laboratory buildings, Tenant fit-out,
Assembly buildings, Residential Buildings and small residential buildings.
Urban districts, Industrial estates and Trading estates.
2.3.2.2. Structure and Application
The DGNB scoring and rating system is based on the performance of six evaluation areas, the topics, with a fixed relative importance. These topics are weighted in the following way [7]:
Ecological Quality: 22,5%; Economical Quality: 22,5%;
Socio-cultural and functional Quality: 22,5% Technical Quality: 22,5%
Quality of the Process: 10%
Quality of the Location: this topic is not included in the final grade but presented separately.
11 Thus, the first five topics flow into a final and last grade, Quality of the Location that is evaluated separately. This topic is not included in the overall evaluation of the building so that each building might be evaluated independent of its location.
Each one of these topics contains several criteria. For each criterion, measurable target values are defined, and a maximum of ten points can be achieved. These measuring methods for each criterion are clearly defined [8].
At the same time each criterion has a weighting factor associated, this way, for instance, the indoor hygiene of an office building is of more importance than the acoustic comfort, so the first has a weighting factor that is higher than the second. The weighting factor can also be zero, if the criterion is not applicable to the specific case on study [8]. Each criteria flows into the overall result in a clearly differentiated way with the support of calculation software that displays the building’s performance.
Depending on the degree of compliance, the evaluated buildings are awarded with the gold, silver or bronze certification (Figure 2).
Figure 2 - Degree of compliance
The grades are given for overall performance of the building as well as for the individual topics [7] [8].
2.3.2.3. Criteria
As already mentioned, the DGNB certification system considers 6 topics. These topics contain a total of 63 individual criteria but the development of 15 criteria was postponed. This way, the certification for “New Construction Office and Administration” in the version of 2012 is based on 48 criteria, from which 6 are evaluated separately (Quality of Location). Therefore, 42 of these criteria are evaluated and flow of the overall score (Table 2).
12
Table 2- DGNB Certification System Criteria
Main Criteria Group Criteria (No.)
7.
Ecological Quality(1) Global warming potential; (2) Ozone depletion potential; (3) Photochemical ozone creation potential; (4) Acidification potential; (5) Eutrophication potential; (6) Risks to the regional environment; (8) Other impacts on the global environment; (9) Microclimate; (10) Non-renewable primary energy demands; (11) Total primary energy demands and proportion of renewable primary energy; (14) Potable water consumption and sewage generation; (15) Surface area usage.
Economic al Quality
(16) Building related life cycle costs; (17) Value stability.
Socio-cultural and Functional Quality
(18) Thermal Comfort in Winter; (19) Thermal comfort in the summer; (20) Indoor Hygiene; (21) Acoustical Comfort: (22) Visual comfort; (23) Influences by users; (24) Roof design; (25) Safety and risks of failure; (26) Barrier free accessibility; (27) Area efficiency; (28) Feasibility of conversion; (29) Accessibility; (30) Bicycle comfort; (31) Assurance of the quality of the design and for urban development for competition; (32) Art within Architecture.
Technical Quality
(33) Fire protection; (34) Noise protection; (35) Energetic and moisture proofing quality of the building's Shell; (40) Ease of Cleaning and Maintenance of the Structure; (42) Ease of deconstruction, recycling and dismantling.
Quality of the
Process
(43) Quality of the project's preparation; (44) Integrated planning; (45) Optimization and complexity of the approach to planning; (46) Evidence of sustainability considerations during bid invitation and awarding; (47) Establishment of preconditions for optimized use and operation; (48) Construction site, construction phase; (49) Quality of executing companies, pre-qualifications; (50) Quality assurance of the construction activities; (51) Systematic commissioning.
2.3.2.4. International Application
The DGNB Certification System can easily be adapted to the climatic, constitutional, legal and cultural particular features of other countries. This is one of the strengths of this System since it allows that the DGNB system might be applied internationally [9].
13 Local application together with a partner organization;
Direct application of the DGNB system.
On the first approach if a DGNB’s suitable partner organization has been established in a country, the DGNB can work in tandem with it on the certification system, regarding the local requirements and the building culture, but always in accordance with the DGNB system [9]. The second approach takes on the cases where there is no DGNB partner organization. In these countries an international version of the DGNB Certification System is available based on the current European norms and standards. The criteria catalogue can be adapted to the local circumstances, by the DGNB GmbH [9].
In many countries the local sustainability experts receive further training and education. These efforts are done with the cooperation of the partner organizations, but also with Private Partnership Projects (PPP), e.g. in Brazil, China and Ukraine [9].
The international application of the DGNB Certification System has already been done in several countries, such as Austria, Denmark, Bulgaria, Switzerland, among others.
2.3.2.5. Advantages of the Certificate
The DGNB Certification System has a set of advantages, among them [8] [9] stand out:
The certificate demonstrates the positive effects of a building on the environment and society;
The certification provides, in an early stage, a high degree of certainty that the goals, in terms of the performance of the building, can be achieved at the time of completion. As the System is present in all stages of the construction, it leads to more transparency
and well-defined processes, minimizing the risks during construction, operation, renovation and removal.
The certificate supports owners and designers in a globally oriented way for the development of sustainable buildings.
It is based on the life cycle of a building.
The German certificate is not only about the ecological aspects but also the economic performance, as well as socio-cultural and functional aspects of buildings.
The certificate system can flexibly be updated. It can easily be adapted to technical, social and international developments.
2.3.3.OTHER EXISTING BUILDING SUSTAINABILITY ASSESSMENT TOOLS
As already mentioned, there are many other Certification Systems. In this sub-chapter, a small description of some of them will be given.
2.3.3.1. BREEAM (Building Research Establishment Environmental Assessment Method) The BREEAM Certification System was developed in the United Kingdom by BRE (Building Research Establishment) in partnership with the private sector and aimed at measuring and
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specifying the environmental performance of buildings. The development started in 1988 and it was launched in 1990. This system has several schemes, each one specifically designed to adapt to a particular kind of building. Examples of those schemes are the BREEAM for offices (designed for office buildings), the EcoHomes (designed for housing buildings) or the
Superstores (designed for new trade buildings), among others [10] [6].
The assessment carried out by this system is done in a similar way to the one made by the DGNB Certification System. The system considers ten different categories: Management; Health and Wellbeing; Energy; Transport; Water; Materials; Waste; Land Use and Ecology; Pollution; Innovation [10].
Each one of these categories contains several criteria to which credits are awarded when certain requirements are checked. To each criterion a weighting factor is allocated according to the importance given by the system. The credits are added together to produce an overall score on the following scale [10] [6]:
<30% = Unclassified ≥ 30% = Pass ≥ 45% = Good ≥ 55% = Very Good ≥ 70% = Excellent
≥ 85% = Outstanding (besides >= 85% percentage score, there are additional requirements for achieving a BREEAM Outstanding rating).
2.3.3.2. LEED (Leadership in Energy & Environmental Design)
The LEED Certification System was developed by USGBS (the U.S. Green Building Council) in the United States in 1999 and it was launched in 2000. This system is based on BREEAM and like the British system there are several schemes of LEED, designed for different uses, including the LEED-NC (new construction), or the LEED-EB (existing buildings), among others [6].
The sustainable buildings are rated from seven categories: Sustainable site, Water efficiency, Energy and atmosphere, Materials and resources, Indoor environmental quality, Innovation and Regional Priority. Like the other certification systems mentioned above, the assessment process of the LEED certification system is done with the attribution of credits to each criterion contained in these categories. Once again, each criterion has a weighting factor associated according to its importance. The total score achieved leads to the assignment of different types of certifications. The LEED considers the following scale [10] [18]:
40-49 points – Certified 50-59 points – Silver 60-79 points – Gold 80-110 points – Platinum
15 2.3.3.3. CASBEE (Comprehensive Assessment System for Built Environment Efficiency) This certification system was presented by the Japanese Sustainability Building Consortium in 2002. The aim of CASBEE is to assess residential, office and school buildings and this tool is in constant adaptation and evolution [10].
This system can be divided on four different tools, each one directed to different users who assess the building at different stages of its life cycle. These four tools are divided in two categories [10]:
The first one focuses on new buildings: it contains a tool for the pre-design stage (directed at owners and designers) that intends to identify the basic context of the project and the other on the environmental project (directed at designers and constructors) that intends to improve the environmental efficiency of the building during the design stage.
The second focuses on existing buildings: it contains an environmental certification tool (for owners, designers and constructors) to classify the existing buildings in terms of environmental efficiency and a tool to assess after the project (directed at owners, designers and operators/ managers) and aims to collect information about how to improve the environmental efficiency of the building during the operation stage.
This system is composed of several categories (Energy Use/GHG emissions; Water Use; Material/Safety; Biodiversity/Land use; Indoor Environment) that contain different criteria. For each criteria a grade from 0-5 is attributed, according to the technical and social patterns of the building [13].
The final classification of the building has 5 levels: S, A, B+, B and C. The higher classification is S [18].
2.3.3.4. HQE (High Quality Environment standard)
The HQE system was developed in France and it was launched in 2005 and was integrated in the standard of the French Association for Standardization (AFNOR) [19].
This system considers four evaluation groups with a total of fourteen unweighted categories [10]:
Eco-construction: Managing the impacts on the outdoor environment; Selection of the materials/Building elements; Sustainable construction site;
Management: Energy; Water demand; Waste Management; Adaptability and durability of the building;
Comfort: Hygrothermal comfort; Sound insulation; Optimization of natural and artificial light comfort; Reduction in sources of unpleasant odors/air pollutants;
Health: Hygienic aspects; Indoor air quality; Drinking water quality. The evaluation system has three performance degrees:
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P – Performant (Good practice, better than basic); TP – Très performant (Best practice, better than basic).
The results of the categories do not flow to an overall score. To achieve the HQE certification, the building has to meet the following requirements:
TP in at least three categories; P in at least four categories; B in seven categories (at most); P or TP in the category Energy.
2.3.3.5. LIDERA (Lead for the Environment)
The LIDERA is the Portuguese certification system and its first version was presented in 2005. This system can be applied to the different stages of the building process (project, construction, operation/use, maintenance and renovation and demolition) and it adopts six main principles [2] [6].
1. Valuing the local dynamics and promote the proper integration, 2. Boosting the resource consumption efficiency;
3. Reduce the impact loads (both in value and in toxicity); 4. Ensure the ambient air quality;
5. Promoting the socio-economic sustainable practices;
6. Ensure the best sustainable exploitation of the built environment, through environment management and innovation.
The LIDERA certification system considers six categories with different intervention areas: Site Integration (soil, ecosystems, landscape and heritage), Resources Consumption (energy, water, materials, food), Environmental Loads (air emissions, waste, outside noise, …), Environmental Comfort (air quality, thermal comfort, lighting and acoustics), Socio-economic Experience (access for all, life-cycle costs, economic diversity, social interaction, …) and Sustainable Use (environmental management and innovation) [6] [2].
To each criteria contained in the intervention areas its performance is assessed on the building and the score flows to the final score of the building [3].
To assess the sustainability of a building performance, degrees from G (less efficient) to A+++ (more efficient) were defined. The E class is the reference and represents the usual practices of the existing buildings in Portugal [2].
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Figure 3- Global Performance Degrees of the LIDERA Certification System
A building is able to get the LIDERA certificate if its performance grade is at least C.
2.3.3.6. SBToolPT (Sustainable Building Tool, Portugal)
The structure of this tool is based on the international certification system SBTool, adapted to the Portuguese reality. The SBTool was developed by the non-profit association iiSBE (international initiative for the Sustainable Built Environment) with the collaboration of teams from more than 20 countries (Europe, Asia and America).
The Portuguese version was developed by the iiSBE Portugal with the collaboration of the University of Minho and the company Ecochoice. This system has specific modules for each type of building and it has 9 sustainability categories that contain several indicators/criteria and summarizes the building performance:
Climate change and outdoor air quality; Land use and biodiversity;
Energy efficiency;
Materials and waste management; Waste efficiency;
Occupant’s health and comfort; Accessibilities;
Awareness and education for sustainability; Life-cycle costs.
This system uses a different approach to weight the criteria, considering the reference value, the best practice value for each criterion and also the value achieved by that criterion.
The categories have also a weight that allows the calculation of the score of each category and of the overall performance of the building. The ranking scale is from A+ to E.
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3
M
ETHODOLOGY
3.1.INTRODUCTION
To achieve the aims of this thesis, the first step was to select the criteria of the study. This choice was made by taking into account the criteria present on the existing Building Sustainability Assessment tools but mainly the criteria considered by the DGNB Certification System. This decision was made because the final objective of this study is the implementation of the new weighting factors for the criteria, on the German certification system, thus all the ten criteria of study are also present on this certification system. Another important aspect of this choice was for all the criteria chosen to be related to the Building Physics. Thus, 10 criteria were selected and this list does not claim to be exhaustive.
After the selection of the criteria a questionnaire was developed with several questions about the ten criteria selected and also about the existing certification systems. This questionnaire was addressed to experts from all over the world and it was sent via e-mail. The objective of this chapter is to explain the methodology adopted in this thesis, since the choice of the criteria to be studied and their description of the development of the questionnaire and its content.
3.2.CRITERIA
As already mentioned, the 10 criteria selected for this study are present on the DGNB Certification System list of criteria. To avoid wrong interpretations or mistakes on the response phase of the questionnaire and make this study trustworthy, it was important to have a clear definition of each criterion present on this study. Thus, the definition of each criterion is in accordance with the definitions present on the DGNB Certification System for the respective criterion.
Thus, the criteria chosen to be part of this study are: Energy Demand;
Thermal Comfort in Winter; Thermal Comfort in Summer;
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Indoor Air Quality; Acoustic Comfort; Visual Comfort;
User Influence on Building Operation; Sound Insulation;
Building Envelope Quality; Fire Protection.
3.2.1.ENERGY DEMAND
The DGNB certification system splits this criterion in two: nonrenewable primary energy
demand and total primary energy demand and share of renewable primary energy. On this
study it was decided to join those two into a criterion called Energy Demand.
The use of nonrenewable fossil energy sources should be minimized. The figure to be evaluated is the amount of nonrenewable primary energy needed for the construction, use, and dismantling of the building. Primary energy is energy from naturally occurring sources. This includes both nonrenewable and renewable energy. Black (bituminous) coal, brown coal (lignite), crude oil, natural gas, and uranium are nonrenewable energy sources; renewable energy includes solar energy, geothermal energy, hydropower, wind energy, and biomass [8]. The demand for nonrenewable primary energy is calculated throughout the building’s lifecycle for construction, maintenance, operation, and dismantling [8].
The total demand for primary energy shall be minimized and the percentage of renewable energy shall be maximized during the life cycle of a property [8]. The total value of primary energy demands are evaluated, as well as the percentage of renewable energy demands, as compared to the total primary energy demands.
3.2.2.THERMAL COMFORT IN WINTER AND THERMAL COMFORT IN SUMMER
The acceptance of the indoor climate is evaluated with focus on the factors: thermal comfort, air quality, noise and illumination. The thermal comfort of a person is closely linked to satisfaction at the work place. On the one hand it is defined by an overall comfort; on the other hand local uncomforting phenomenon can impact the thermal comfort. Thus, a person can feel thermal comfort but can be adversely affected by local draught on a body part. To assure thermal comfort all criteria have to be fulfilled [8].
For the evaluation of the thermal comfort, the following list of criteria are assessed: Operative temperature (quantitative);
Draught (qualitative);
Asymmetry of radiation temperature and flooring temperature (qualitative); Relative humidity (qualitative);
21 Required records include documentation of the heating system design condition as well as documentation of the air conditioning plant and the characteristics of the air exhausts if applicable [8].
3.2.3.INDOOR AIR QUALITY
The goal is to assure the indoor hygiene and to avoid negative impacts on the user’s state of health.
Through the choice of odorless and low-emission products the basis for low emission concentrations of fugitive and smell active substances can be established for interior spaces in the planning phase. The successful planning is ascertained by measuring the TVOC-concentration of the room air at the latest 4 weeks after completion of the building. The completion time point is defined when all stages that affect the quality of the interior air are terminated including building services and commissioning of the sanitary and ventilation plants but prior to furnishing by the user. With a checklist the following criteria are evaluated [8]:
Indoor hygiene – fugitive organic substance (VOC); Indoor hygiene – felt air quality, unwanted odors;
Indoor hygiene – microbiological situation, mould build-up.
3.2.4.ACOUSTIC COMFORT
The aim is to achieve a low level interference and background noise with speech intelligibility in all rooms to avoid affecting use, health and capability of the users. The lower the level of interference and background noises is, the less detraction and detriment to health and capability. High speech intelligibility in communication rooms and high absorbability of sound propagation to restrict the mutual interfering potential is of advantage [8].
For the evaluation of offices different acoustic input parameters are necessary:
Average resulting overall noise pressure level LA,F,Ges in dB(A) as expression of the level of interferences;
Reverberation period T in s, oriented on the values according to DIN 18041w (T/TDIN 18041);
Absorption of sound propagation in multiple-person offices DA in dB/m.
Sound propagation is ascertained via calculation or measurement. Furnishing is only allowed to be taken into consideration if it is part of the architecture and building design.
3.2.5.VISUAL COMFORT
Visual comfort shall be achieved by balanced illumination without appreciable interferences such as direct and reflected glare, a sufficient illumination level and the possibility to adjust illumination individually to the particular needs. Vitally important for the workplace contentment is the view that informs about time of day, location, weather conditions etc. Further
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criteria are nonglaring, light distribution and spectral colour in the room. The requirements are valid both for illumination by daylight and artificial light [8].
By an early and integral daylight and artificial light planning, a high quality of illumination can be created with low energy demands for illumination and cooling. Furthermore, a high degree of daylight use can enhance workplace capability and health and reduce the operational costs. In a checklist the visual comfort is evaluated:
Daylight availability for the entire building (quantitative);
Daylight availability for the permanent workplaces (quantitative); Visibility to the exterior (quantitative);
Non-glaring – daylight (quantitative); Non-glaring – artificial light (quantitative); Light distribution – artificial light (quantitative); Color reproduction and spectral color (quantitative).
3.2.6.USER INFLUENCE ON BUILDING OPERATION
Goal is the maximization of the user influence capabilities in the sectors ventilation, sun protection, visor, temperature as well as regulation of daylight and artificial light at the workplace.
Within an early and integral planning of measures that convey the users influence at the workplace, comfort can be conveyed. Advancement of comfort leads to increased satisfaction and achievement of users in office and administration buildings. A checklist of the possible influence by users is evaluated with the following criteria:
Ventilation; Sun protection; Visor;
Temperatures during the heating period; Temperatures outside the heating period; Regulation of daylight and artificial light.
3.2.7.SOUND INSULATION
Noise protection shall be improved. Minimum requirements of structural noise protection are defined in DIN 4109. This only addresses the unacceptable but not automatically all possible noise pollutants. Additional requirements to noise protection in office buildings are: avoiding loss of concentration, protection of privacy and confidentiality, and consideration for people with limited hearing.
Measures that exceed the minimum noise protection requirements lead to a better score. A pointless exceeding of the standards shall be avoided. The quality of noise protection of building parts is determined from the certificate of noise protection or the quality of the
23 specified building parts. It is evaluated if the building parts comply with the regulations of DIN 4109 supplement 2 and where the regulations are exceeded:
Airborne noise protection against surrounding noise;
Airborne noise protection against other workplaces and against the own workplace; Impact-sound protection against other workplaces and against the own workplace; Structure-borne sound protection against other workplaces and against the own
workplace.
3.2.8.BUILDING ENVELOPE QUALITY
The energy demand for the space conditioning shall be minimized, high thermal comfort shall be assured, and structural damages shall be avoided. The quality of heat insulation and moisture-proofing of the building’s shell shall be optimized.
Basis of the requirements are the specifications of EnEV 2007, DIN 4108, and DIN EN 12207. A higher quality increases the score. Individual requirements for the parts of the building’s shell are described.
The building’s shell is evaluated with a checklist of the following criteria: Average heat transmission coefficient (qualitative);
Consideration for thermal bridges (qualitative); Permeability of joints (qualitative);
Formation of condensate (qualitative); Air change rate (quantitative).
3.2.9.FIRE PROTECTION
The quality of fire protection measures shall be increased. The main cause of death involving fire in buildings is toxic smoke. Measures that exceed the fire protection regulations can be rated positively. However, fire protection measures that exceed the legal regulations should also consider the total economic impact as well as additional emissions caused by the addition amounts of raw materials and supplies.
A checklist evaluates the following issues, as long as they exceed the minimum requirements set by the building authorities:
Is the building equipped with an area-wide fire alarm and electro acoustic alarm system, so that a prompt response in a hazardous situation is possible?
Is a sprinkler system present that delays the fire’s expansion, and that enables the fire department to carry out effective fire fighting at an early stage?
Can the ventilation system be used for smoke extraction in case of fire, and does the system prevent a re-circulation of the (smoke-filled) air during the smoke extraction? Do air duct systems have fire dampers to prevent the distribution of smoke during a fire?
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Is the spreading of smoke and fire avoided beyond the required amount by reducing the sizes of the fired compartments?
Is spreading of smoke and fire avoided through structural measures beyond the required amount?
The necessary parameters for the calculation can be extracted from the state building code, the fire protection concept, and the announcement documents.
3.3.QUESTIONNAIRE
After the selection and clear definition of each criterion having been made, a questionnaire (Figure 4) was developed. With this questionnaire it was expected to find valuable data that would make the development of the weighting factors possible for the criteria.
This questionnaire was sent via e-mail to University professors, researchers and also to auditors and consultants of several existing Building Sustainability Assessment tools. All the people chosen to be part of this study have knowledge of building physics and sustainable constructions and/or have experience with the Certification Systems for sustainable constructions.
The questions present on this questionnaire were not mandatory. In order to make this study trustworthy a screening of the answers was done. At this screening, people who answered to less than 75% of the questions were eliminated from the data analysis.
A total of 229 answers has been collected but, after the screening was done, a total of 210 valid answers resulted. The statistical analysis made in this study is based on these 210 responses. In this questionnaire several questions with respect to the 10 criteria were made, but also questions related to personal experiences with the Building Sustainability Assessment tools that each person was familiar with, as well as some personal questions to help in the analysis of the collected data.
Figure 4 - Homepage of the questionnaire
25 3.3.1.DESCRIPTION OF THE QUESTIONNAIRE
Importance of the Criteria
One of the key questions on the questionnaire dealt with the importance in terms of sustainability of each of the criterion, on the list of 10 criteria, from the perspective of the people surveyed. The surveyed people were asked to “Rate each of the following criteria taking into account the importance in terms of sustainability”. For the assessment, a scale from 1 to 6 was used, in which 1 indicates “very important” and 6 “very unimportant”. An option “NA/Unknown” was also available to those people who did not want or did not know what to answer for each criterion (Figure 5). To avoid wrong interpretations by the people inquired, each criterion had a small description. All these descriptions are in accordance with the ones present on the DGNB Certification System.
Figure 5 - First question of the questionnaire about the importance of the criteria
Frequency of the deficiencies
Another important question on this questionnaire was about the frequency of occurrence of deficiencies. With each one of the 10 criteria on study several deficiencies were associated (Table 3). Thus, it was asked “With which frequency do you think, the following deficiencies occur in buildings?”. A scale from 1 to 6 was used, in which 1 corresponds to “always” and 6 to “never”. Once again the people surveyed had the “NA/Unknown” option, in the cases of people who did not know or did not want to answer (Figure 6).
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Table 3- List of the 10 Criteria on study and respective deficiencies associated
Criteria Deficiency
Energy Demand Excessive energy consumption
Thermal Comfort in Winter Cold room temperature, cold walls. Thermal Comfort in Summer Overheating in Summer
Indoor Air Quality Poor ventilation, presence of volatile organic compounds.
Acoustic Comfort High background noise and reverberation time levels.
Visual Comfort Deficient artificial light distribution, poor daylight availability.
User Influence on Building Operation Impossibility to control ventilation, temperatures. Sound Insulation Pointless exceeding of the standards.
Building Envelope Quality Poor air permeability class, condensation within structure.
Fire Protection Absence of sprinkler system, automatic smoke detectors.
Again, this list of deficiencies is present on the DGNB Certification System.
Figure 6- Extract of the questionnaire - Question about the frequency of occurrence of deficiencies on buildings
27 As it is possible to see on the Figure 6, to each criterion a description of the deficiency related with that criterion was associated.
Extent of deficiencies
Another question was made about the personal experience of the people surveyed with the deficiencies related to the ten criteria in the study.
It was asked, “To what extent have you personally suffered at your work or home from any of the deficiencies belonging to:”. The deficiencies present on this question were the same as the ones that were asked about on the question about their frequency of occurrence and can be consulted on Table 3. For the assessment a scale from 1 to 6 was used, in which 1 indicates an “Extremely large extent” and 6 indicates an “Extremely small extent” and it was once again possible to answer “NA/Unknown” (Figure 7).
Figure 7- Extract from the questionnaire- Extent of the deficiencies
With this question the intent is to find out whether the answers of the people surveyed were or not influenced by their personal experiences at their home and/or work.
Building Sustainability Assessment tools
After the questions about the ten criteria, some questions about the building sustainability assessment tools were made. At first, it was important to know if the people surveyed had or not any kind of experience with these certification systems. Thus, it was asked “Have you had experiences with Building Sustainability Assessment tools (DGNB, BREEAM, LEED, LIDERA, etc.)?”. With this question it was already possible to divide the people surveyed into two groups, which could prove to be important later, in the data analysis: The people with experience with BSA tools and the people without experience with these tools.
